Yield strength of fine-rolled rebar refers to the yield limit of fine-rolled rebar when yielding phenomenon occurs, that is, the stress to resist trace plastic deformation. Greater than this limit of external force, will make the parts permanent failure, can not be recovered.
The yield strength of fine-rolled rebar are affected by intrinsic and extrinsic factors:
Intrinsic factors are: bonding, organization, structure, atomic nature. Such as the yield strength of metals and ceramics, polymer materials can be compared to see the effect of the bond is fundamental. From the influence of organization and structure, there can be four kinds of strengthening mechanism to affect the yield strength of metal materials, which is solid solution strengthening, deformation strengthening; precipitation strengthening and diffusion strengthening and grain boundaries and subcrystalline strengthening. Precipitation strengthening and fine grain strengthening are the most commonly used means of increasing the yield strength of materials in industrial alloys. Among these strengthening mechanisms, the first three mechanisms reduce plasticity while increasing the strength of the material, and only fine grain and subcrystalline can increase both strength and plasticity.
The external factors affecting the yield strength of fine-rolled rebar are: temperature, strain rate, stress state. As the temperature decreases and the strain rate increases, the yield strength of the material increases, especially the body-centered cubic metal is particularly sensitive to temperature and strain rate, which leads to the low temperature embrittlement of steel. Yield strength is an essential indicator of the intrinsic properties of a material, and the value of yield strength varies at different stress states.
